Automatic motor-starter.



W. G. YATES. AUTOMATIC MOTOR STARTER.

APPLICATION FILED MAY 9, 1908.

Patented Jan. 26, 1909.

WITNESSES Rm.

TR TR.

UNITED srAtrns ENT OFFICE.

WILLIAM c. YATES, or soars-senor, New YORK, ASSIGNOR TO GENE'RAL'ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ATTTOMATIG ROTOR-STARTER.

Specification of Letters Patent. Application filed May 9, 1908. Serial No. 431,935.

mesa Ian. as, 1909.

' To all whom may concern:

Be it. known that-I, WILLIAM C. YATES, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Automatic Motor-Starters, of which the following is a specification.

This invention relates to means for controlling electric motor circuits and has for its object the provision of a device whereby an electric motor may be started and brought up to running speed in a reliable, safe andefiicient manner. My invention relates more specifically to the starting of alternating current motors of the type whichare controlled by connect- 1 ing them to a source of low voltage for starting and then increasing the impressed voltage for running. I

One of the objects of my invention therefore is to provide a simple and eflicient automatic starter for alternating current cir cuits by means of which motors may be controlled from a distance either manually or by automatic switching devices such as pressure governors, float switches, and the like.

In the application filed by Charles -D.

. -Knight, Serial No. 289,774, there is dis closed a starting mechanism of the type above described for starting a three phase. motor. In the starting of two phase motors, however, with a device such as is described in said application, it has been observed that if one phase of the transmission line is grounded or is short-circuited, the motor will run single. phase thus overheating an burning out the motor.

- One of the objects of my invention therefore is toprotect a device of this sort when usedon two phase circuits. This I accom- A is an induction motor of the squirrelcage type; B is the compensator or autotransformer; C is the starting switch; D is the-running switch; and E is the master controller. The starting switch 0 is arranged to, connect the motor A to the two phase mains through the transformer B while running switch D connects the motor directly to the'line. the no-voltage magnet 11 is energized as is also. the starting switch C, the locking mag- .net 12 and the solenoid 13 of the master controller E. These circuits are closed by an electromagnetic switch 14 which is energized by phase a a of the circuit while the energizing circuit is tapped oil of the phase I) I). W hen therefore the switch 1'0,'which may be operated manually or otherwise, is closed the switch C is operated, connecting the two pghase mains a a and b b to the transformer through the three bridging contacts 15, 16, and 17, and at the same time connecting the motor A to the transformer through the bridging contacts 18, 19 andj20. When the switches are closed by the solenoid oi the switch C, the solenoid is deenergized by the; liftin of the switch lever 21 pivoted at 22, but the core is held in its raised position by means of the latch 23 which is moved into a slot 24 in the core by means of the locking magnet 12. In the meantime the solenoid 13 of the master controller, which has been energized, has caused its core 25 to travel upwards against the retardation of the dashpot 26 until'the bridging contact 27 opens the circuit of-the locking magnet 12 and at the same time closes the circuit of the solenoid switch D. This causes the starting switch E to be opened, cuttingoii the transformer from the line and from the motor, and at the same time switch D closes the circuit through the motor at the contacts 28 and 29. These contacts are held up by means of the novoltage magnet 11 which is controlled from both phases of the circuit. It now one of the phases, as for instance a. a, is short-circuited,

.the .magnet 14 would be deenergized as.

would magnet 11 whereupon all of the parts would return to starting position. The

W'hen the switch 10 is closedsame would be true if the phase I) I)" should be short-circuited. In this manner I have protected the device against danger from-the grounding of either phase, and while I have described my invention in connection with a specific type of mechanism arranged to operate in a specific way, it should-be understood that I do not wish to limit my invention thereto except in so far as it is limited by the scope of the claims annexed hereto. What I claimras-newand desire to secure by Letters Patent of the United States, is,

1. The combination with an alternating current motor and a polyphase supply circuit of a transformer, a plurality of automatically-operated switches, forfirst connecting the motor to the supply circuit through the transformer and then connecting the motor directly to the supply circuit, and a no-voltage magnet responsive to any phase of the I circuit.

2. The combination with an alternating current motor and a two hase supply circuit, of a voltage controiling device, two switches arranged to connect said motor in difl'erent relations to said controlling device tor starting and for running, and a no-voltage magnet for the running switch controlled by both phases of the circuit.

' ity of automatically operated switches for first connecting the motor to the supply circuit through the controlling device and then connecting the motor directly to the supply circuit, a no-voltage magnet energized by one phase, and an electromagnetic switch in the energizing circuit of said magnet controled by the other phase 5. The combination with an alternating current motor and a two phase supply circuit, of a voltage controlling device, two

switches arranged to connect said motor in different relations to said device for startin and for running, a control system for sai switches comprising means automatically operating to close the starting switch and then close the running switch and 0 en the starting switch after a predetermine interval, and a no-voltage magnet for the running switch controlled by both phases of the circuit.

6. The combination with an alternating current motor and a two hase supply circuit, of a voltage controfiing device, two switches arranged to connect said motor in different relations to said device for starting and for running, a control system for said switches -comprising means automatically- 0 crating toolose the starting switch and tli enclose the running switch and 0 en the starting switch aftena predetermine interval, and a no-voltage 'magnet for the run 'ning switch energized by one phase and having its energizing circuit controlled by the other phase.

a 7. The combination with an alternating current motor and a two hase supply circuit, of a voltage controlling device, two switches arranged to connect said motor in different relations to said device for startin and for running, a control system for sai switches comprising means automatically operatin to close the starting switch and then close t e running switch and open the starting switch after a predetermined interval, a no-voltage magnet for the running switch energized by one hase, and an electromagnetic switch in t e energizing circuit of said magnet controlled by the other phase.

In witness whereof I have hereunto set my hand this 8th day of May,- 1908.

WILLIAM C. YATES. Witnesses:

BENJAMIN B. HULL, HELEN Onronn. 

